深厚覆盖层上高心墙堆石坝坝顶开裂特征及原因研究

国内多座深厚覆盖层上兴建的高心墙土石坝坝顶均出现不同程度的开裂,对坝体的长期安全稳定构成威胁,受到业内广泛关注。通过地质雷达、高密度电法等物探技术确定某高心墙堆石坝顶裂缝时空分布情况,根据变形实测资料分析了其变形破坏特征,并结合工程建设情况、结构特征、运行情况等对开裂原因进行分析。结果表明坝顶裂缝产生的根本原因是土体承受的应力超过其抗拉强度或抗剪强度后而发生的破坏,直接原因为坝顶的不均匀沉降,其中水荷载、湿化变形、蓄水速度、坝顶材料特性是坝顶不均匀沉降的关键影响因素。

Research on the Cracking Characteristics and Causes of Dam Crest in High Core Wall Rock-fill Dam on the Deep Overburden Layer

Cracking with different degrees appears in some high core wall rock-fill dams built on deep overburden layer in China,which threatens the long-term safety and stability of dams and has attracted widespread attention.Based on the cracking mechanism of rock-fill dams,coupling relationship between the cracking modes and the monitoring characterization is investigated.Take a high core wall rock-fill dam with cracking in dam crest as an example,the spatial,temporal distribution and the failure characteristics of deformation are studied by using the geological radar,high density electrical method and actual monitoring data.The results show that the stress of soil exceeds its tensile strength or shear strength,which is the fundamental cause of cracking in dam crest.The direct reason is the non-uniform settlement of dam crest,and it is influenced mainly by the water loads,wetting deformation,storage velocity and material characteristics.